TV-Series
Description
Otonari-san is a supporting character in the anime Sasaki and Peeps. Her name simply means neighbor, and the story regularly refers to her that way because she lives in the apartment next door to the protagonist, Sasaki. She is a junior high school student whose surname, Kurosu, is mentioned in the story, although her given name is never revealed.

Her background is marked by hardship. Her mother is neglectful, and because of that home environment, Otonari-san often spends time sitting alone outside her own apartment door, which is where she regularly encounters Sasaki. Her difficult family life led her to abandon any hope of further education, and her schoolwork has fallen into disarray. At school she has no friends and lives a very isolated, lonely existence.

In terms of personality, Otonari-san is a yandere type of character, meaning her affection for Sasaki is sincere and caring but also crosses into unhealthy and extreme obsession. Her deep attachment to him is the emotional center of her character, and her feelings are shaped by the neglect and isolation she has experienced. Her primary motivation and wish is for Sasaki to feel desire for her, and much of her behavior revolves around that longing.

Within the larger story, she becomes a key figure in the supernatural conflict. When she was nearly assaulted by her mother's boyfriend, she was chosen by the demon Abaddon to take part in a deadly game hosted by an angel and a demon, becoming one of Abaddon's apostles. She fights on the demon side of that death game. Through these events, she loses her mother and her home, leaving her with nothing from her former life.

Her relationship with Sasaki is the most important one in her life, mixing genuine care with obsessive devotion. Her bond with the demon Abaddon defines her role in the death game, as she serves as one of his chosen fighters. After losing her family and home, she is taken in by Futari Shizuka, who becomes her caretaker.

Her development follows her transformation from a lonely, neglected schoolgirl into a participant in the battle between angels and demons. Despite the loss of her mother and her previous life, her fixation on Sasaki remains a constant, and she continues to be drawn into his world.

As for notable abilities, Otonari-san is established as an apostle of Abaddon and a combatant in the death game, fighting on the demon side. The story does not clearly define a specific set of unique powers for her beyond her involvement and role in that supernatural contest.